JPS60260102A - Method of producing thick film positive temperature coefficient semiconductor element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a thick-film positive temperature coefficient semiconductor element that does not require glass frit, among planar heating elements used for heat insulation and heating of equipment, etc. It is.

Conventional configuration and its problems Elements made of B a Ti 05-based semiconductors have switching characteristics in which the resistance value increases rapidly above a predetermined temperature and self-heating characteristics after switching. It is widely used because it has a control function and does not require an external control circuit.

Conventional positive temperature coefficient thermistor heating elements were obtained by press-molding BaTiO3-based semiconductor powder and then firing it, but it was considered difficult to obtain a practical thick film positive temperature coefficient thermistor heating element. .

Conventionally, the following methods are known as methods for processing a B a T i O5-based semiconductor into a film.

■ After forming into a disk shape, the fired product is polished into thin pieces.

■ Form a thin film on the substrate by vacuum evaporation.

(2) Conductive additives and glass frit are added to B aT i 05 semiconductor powder to form a paste, which is screen printed on a substrate and then fired.

However, in the method (2), since the BaTiO3-based semiconductor has a large crystal grain size and is brittle, it is extremely difficult to polish the BaTiO3-based semiconductor into a film. Furthermore, the method (2) is cumbersome to operate, and it is difficult to obtain a large amount of power suitable for the heating element.

Furthermore, method (2) above tends to have a high sheet resistance and is difficult to control, is not suitable for heating elements, and requires preparing and firing the glass frit in advance, which is troublesome and the material of the glass frit is difficult to control. Depending on BaTiO
It deteriorates the switching characteristics and self-heating characteristics of the 3-based semiconductor. By adding glass frit, V) B, aTi05 semiconductor and glass frit are susceptible to thermal shock due to the difference in heat resistance and coefficient of thermal expansion, and heat conduction is hindered. Furthermore, it is difficult to uniformly mix conductive additives and glass frit, which is one of the causes of variations in properties.

Purpose of the Invention Therefore, the present invention solves the drawback of the prior art, which is the complexity of manufacturing, and creates a film with excellent thermal shock resistance, thermal conductivity, and uniformity by forming a thick film without using glass frit. characteristic'
It is an object of the present invention to provide a method for easily manufacturing a thick film type positive characteristic semiconductor device having the following characteristics.

Structure of the Invention The method for manufacturing a thick film type positive temperature semiconductor device of the present invention includes
1.0-60.0% by weight of PrP in iO3-based semiconductor powder
In addition, the present invention attempts to obtain a υ thick film type positive characteristic semiconductor element by coating a paste-like mixture on a substrate to form a thick film and then firing it.

In the conventional method of using conductive additives and glass frit, a conductive additive is required for electrical connection between BaTiOy-based semiconductor powders, whereas glass frit is required to physically connect BaTiO3-based powders together. was necessary.

However, the present invention is characterized in that P is used as a material that functions as both a conductive additive and a glass frit. This PrP is a conductor at room temperature, and when the temperature reaches 1000-1100° C. or higher, a portion of it decomposes and P2O5 precipitates on the particle surface, but the inside of the particle remains intact and decomposition is prevented by the P2O5 film on the surface.

Therefore, when BaT i 05 semiconductor powder and PrP powder are mixed and fired, P2O precipitates on the surface of PrP.
5 plays the same role as a glass frit, and the inside of the particle plays the role of a conductive additive, so a thick film type positive temperature semiconductor element that does not require a glass frit can be obtained by simply adding PrP.

Furthermore, by adding a conductive metal, the thermal conductivity becomes better than that of glass frit, which has poor thermal conductivity, and the thermal shock resistance also improves.

DESCRIPTION OF EMBODIMENTS Below, embodiments of the present invention will be specifically explained with reference to FIG.

Example 1 BaT 105 K 1.0 mo/l/% cQ N
After adding b2O5 and firing at 1300℃, it is crushed to obtain Ba
A T103-based semiconductor powder is obtained. 7.0% by weight of PrP powder based on the total weight is added to the BaTiO3-based semiconductor powder and mixed uniformly, and α-terpineol is further added to prepare paste mixture 1.

On the other hand, a pair of electrodes 3.4 made of a conductive material such as ig are provided in advance on a substrate 2 made of U, O5, etc., and a part of the electrodes 3.4 remains on the electrodes 3 and 4. The paste mixture 1 is applied by screen printing or the like, heated from room temperature to 1350° C. at a rate of 10° C./min, held for 1 hour, and then allowed to cool in a furnace. In this way, a thick film type positive characteristic semiconductor device was obtained.

Example 2 In the same manner as in Example 1, 3.0 mol of La2O3 is added to B a T i O5 and fired at 1250°C, followed by pulverization to obtain a BaTiO3-based semiconductor powder. The BaTiO
26.0% by weight of pr based on the total weight of the 3-based semiconductor powder
P powder is added and mixed uniformly, and α-terpineol is further added to form paste mixture 1. Next.

As in Example 1, the electrode 3 is placed on the substrate 2 in advance.
.
After raising the temperature to 0° C. and maintaining it for 30 minutes, it is allowed to cool in the furnace.

In this way, a thick film semiconductor device was obtained.

The sheet resistance at room temperature of the thick film semiconductor device thus obtained was 4.7 Ω/c'A in the case of Example 1, and 2.3 Ω/cU in the case of Example 2. The relationship between temperature and resistance value was as shown in FIG. In FIG. 2, A shows the characteristics of the device obtained in Example 1, and B shows the characteristics in Example 2.

Effects of the Invention As described above, according to the manufacturing method of the present invention, PrP powder plays both the roles of a conventional conductive additive and a glass frit, and has sufficient effects on electrical and physical connections. Finally, a thick film positive characteristic semiconductor device can be obtained without a glass frit.

Further, by using PRP, which is a conductive metal with good heat conduction, instead of glass frit, which has poor heat conduction, the thermal shock resistance is improved due to the good heat conduction. Furthermore, since it can be manufactured by screen printing or the like, the work is easy and mass production is possible.

In the present invention, any BaTiO3-based semiconductor powder may be used as long as it is made into a semiconductor by adding various additives to BaTiO3. In addition, the addition amount of PrP powder was specified to be 1 to 60% by weight based on the total weight, because if it was less than 1% by weight, the area resistance would be too large and it would be unsuitable for a heating element. Physical fixation is not possible,
On the other hand, if it exceeds 60% by weight, the sheet resistance becomes too small.
This is because the self-control characteristic (PTC characteristic) becomes small, making it unsuitable for a heating element. Furthermore, any material that can be used to form a paste by using an organic solvent (α-terpineol in the example) to form a paste from BaTiO3 semiconductor powder and PrP powder may be used.

As described above, according to the present invention, it is possible to easily manufacture a thick film type positive characteristic semiconductor device that does not require a glass frit.
Its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a thick film type positive characteristic semiconductor device obtained by the method of the present invention, and FIG. 2 is a diagram showing the relationship between temperature and resistance value of the device according to an embodiment of the present invention. . 1...Paste mixture, 2...Substrate, 3
, 4...electrode.

Claims (1)

[Claims] PrP in BaTiO3-based semiconductor powder from 1.0 to 60.0
1. A method for manufacturing a thick-film type positive characteristic semiconductor element, comprising: adding a paste-like mixture by adding % by weight to a substrate to form a thick film, and then firing the mixture.